Search

This research aimed at providing a first evaluation of willow tree (Salix acmophylla) irrigated by secondarily-treated wastewater as a fodder for goats. The nutrient and mineral contents in stems and leaves of two willow types (termed “red” and “white” for their bark color) and the concentration of secondary compounds were established. The adaptation of naive goats to willow forage and its effect on the milk composition of late lactating goats were also studied. Willow fodder was composed of 45% leaves and 55% stems, on a DM basis; the weighted content of CP, ME, NDF, Ca, and P were (on a DM basis): 13.6%, 1.8 Mcal, 44.9%, 1.1%, and 0.2%, respectively. Lead, nickel and cadmium were found below the detection threshold in willow fodder and the concentrations of metals did not exceed the recommended ranges in feed. Intake was higher for red than for white willow fodder. The adaptation rate to white willow was low (27 g/d) but steady and intake was similar to that of clover hay after one week. White willow contained 1.2-fold more salicin (P

Willow (Salix spp.) is grown for energy biomass in temperate regions and is also a promising source of feed for ruminants. Willow fodder contains high concentrations of beneficial plant specialized metabolites (PSMs). We investigated the efficacy of ensiling willow fodder in 1.5 L jars without (control-C) or with silage additives (lactobacilli-LAB, molasses-M, or the combination MLAB), and the effects on nutritional attributes of ensiling willow in 60 L drums with LAB. We also assessed the effect of ensiling willow fodder on PSMs by liquid chromatography / time-of-flight / mass spectrometry (LC-TOF-MS). Exact or tentative compound identification was established, depending on availability of appropriate standards. In jars, LAB-supplemented silages reached lowest pH (4.2). M-supplemented silages had lower aNDF and aADF contents. IVDMD was higher in M than in C, and the contents of crude protein (CP) were not affected by silage treatments. Ensiling in drums did not affect the major nutritional components of willow fodder. Even though phenylalanine, arginine, tyrosine, histidine, and methionine, but not tryptophan, were increased 3.8–7.9-fold by ensiling, the finding is of low importance, as free amino acids are totally degraded in the rumen. In contrast, the main PSM, i.e., the salicinoid salicin was 74 % de-glycosylated, concomitantly with a ten-fold increase in salicylic acid concentration and with the appearance of acetyl-salicylic acid; likewise, the flavonoids hyperin and rutin were 66 % de-glycosylated, consequent with a 48-fold increase in quercetin concentration. As the bio-availability of the quercetin aglycone is inferior to that of its glycosylated counterparts, ensiling might affect the nutraceutical value of willow fodder. Likewise, catechin, gallocatechin and epicatechin were totally metabolized by ensiling. Overall, ensiling willow fodder (with LAB) does not affect the nutritional attributes of willow fodder but it greatly alters its PSM concentrations and, possibly impairs its nutraceutical value. However, as anti-oxidative activity is supposed to increase, following de-glycosylation, further research is needed to evaluate a possible trade-off on nutraceutical value between the glycosylated and aglycone forms of phenolics contained in willow fodder.

The yield (kg ha −1 ) and quality (weight, total soluble solids (TSS%), TSS:acid ratio, antioxidative activity in juice and peel) of “Sweetie” ( Citrus maxima × C. paradisi , also known as oroblanco) fruit grown on the non-traditional ‘Poorman’s Orange’ rootstock were similar to and often better than that of “Sweetie” grown on the commercial standard sour orange rootstock, which is susceptible to tristeza. Yield and quality of fruit grown on ‘Swingle’ citrumelo rootstock were inferior to that of sour orange. Fruit grown on ‘Marsh’ grapefruit as a rootstock were of similar or slightly lesser quality than ‘Poorman’. “Sweetie” fruit grown organically were higher in TSS% and titratable acidity than those grown in a conventionally-managed grove, but with a significant decrease in yield, regardless of rootstock.

We investigated the morphological and physiological bases of drought tolerance in rocket (Eruca sativa) and lettuce (Lactuca sativa) seedlings as induced by pre-exposure to different ratios of red (R) and blue (B) LED light. Seedlings were grown for 17–18 days under white (control), 100R:0B, 75R:25B, 50R:50B, 25R:75B, or 0R:100B LED lighting at 156 μmol/m2/s. All seedlings were moved under white fluorescent lights 17–18 days after sowing. Half the seedlings were then droughted for 7 days, followed by re-irrigation for 7 days, while the other seedlings remained fully irrigated. Exposure to combined red and blue wavelengths promoted morphological development (leaf area, number of open leaves, leaf specific weight), as well as pigment (chlorophyll, carotenoids) and secondary metabolite (flavonoid) biosynthesis in both species. Morphological and physiological characteristics were more enhanced by monochromatic red or blue light exposure in lettuce than in rocket. Rocket grown under combined R:B lighting, and lettuce grown under 100 % red or blue LED light suffered most from drought (in the form of lower relative water content (RWC) and increased membrane leakage), despite increased ABA concentrations and antioxidant activity at mid-drought. In lettuce, but not in rocket, there was a positive residual effect of LED pre-treatment on fresh weight of droughted and re-irrigated plants. Increased concentrations of antioxidant metabolites did not correlate with tolerance to drought. All combined R:B light treatments increased stomatal density in both rocket and lettuce. All LED regimes which resulted in increased stomatal aperture area per unit leaf area (AALA) (μm2 aperture/cm2 leaf) resulted in decreased RWC at the end of drought. Stomatal AALA was negatively correlated with end-drought RWC (r = -0.89, p = 0.02) in rocket, but not in lettuce. The relationship between stomatal development and antioxidant activity on drought tolerance appears to be species-specific. The benefits provided to two leafy green species when grown under LED lights must be balanced against the resulting vulnerability to drought.

Cuttings of both `Rehovot' and `Tzfat' land-races of myrtle, when sampled throughout the year, had a significant temporal variation in the percentage of successful rooting. The rooting percentage of cuttings taken during December–February reached 70%, while only 20% of the cuttings taken during May–August successfully rooted. The `Rehovot' type was sensitive to aeration in the rooting medium, while the `Tzfat' type rooted equally well in all media. Treating cuttings with 2,6-dihydroxy-acetophenone before dipping in rooting hormone (IBA) did not enhance rooting of `Rehovot', but increased rooting in `Tzfat' myrtle by an average of 6%.

Mango fruits (Mangifera indica L. cv. Nam Dokmai) were held for 3 days at 38°C and then transferred to 20°C. Fruits placed directly at 25°C after harvest reached their peak ethylene production after 4 days, while the heated fruit took 9 days (6 days after the end of the heat treatment). The 1-aminocyclopropane-1-carboxylic acid (ACC) content paralleled that of ethylene production in unheated fruits, with highest content occurring on day 4. In heated fruit, ACC content continued to increase for 8 days following the heat treatment. The 1-aminocyclopropane-1-carboxylic acid synthase (ACS) activity in unheated fruit was also highest on day 4. In heated fruit the activity was undetectable following heat treatment, but recovered partially during the ripening period. Initial ethylene production from discs with peel was 6-fold higher in unheated fruit than heated, although afte r6ho fincubation the production from both was similar. Activity of 1-aminocyclopropane-carboxylic acid oxidase (ACO) in the discs also showed an 8-fold difference in initial activity in heated versus unheated discs with peel. This difference disappeared during incubation of the discs. In heated discs without peel, both ethylene and ACO activity remained lower than in discs with peel, and the differences between heated and unheated fruit discs were more pronounced. We conclude that the inhibition of ethylene production found during heat treatment is due to inhibition of both ACS and ACO. ACO recovers full activity following heat, while ACS activity recovers only partially, but enough to allow the heated fruit to achieve an ethylene peak. © 1999 Elsevier Science B.V. All rights reserved.

Summary The relationship between softening, pectic substances, polygalacturonase (EC 3.2.1.15), pectinesterase (EC 3.1.1.11) and β-galactosidase (EC 3.2.1.23) during ripening of heated and non-heated mango (Mangifira indica L.) fruits cv. Nam Dokmai was investigated. Fruit softening was accompanied by a progressive increase in water-soluble and ammonium oxalate-soluble pectin and a progressive decrease in alkali-soluble pectin. Polygalacturonase and β-galactosidase activities increased while pectinesterase activity decreased continuously during softening. Heating fruits for 3 days at 38 °C resulted in an increase in softening, ammonium oxalate-soluble pectin and activity of β-galactosidase, and a decrease in alkali-soluble pectin and activities of polygalacturonase and pectinesterase, while heating had no pronounced effect on water-soluble pectin. Softening of ripening mango fruits was more closely related to changes in β-galactosidase activity than to polygalacturonase and pectinesterase activities. The possibility that softening of Nam Dokmai fruits is affected by mechanisms other than involvement of only polyglacturonase and solubilization of the polygalacturonide backbone of the pectin is discussed.

Sodium bicarbonate (SBC) inhibited in vitro mycelial growth of A. alternata, Fusarium spp. and R. stolonifer. SBC action was fungistatic rather than fungicidal. Coating commercially harvested ‘Galia’ and ‘Ein-Dor’ melons with wax containing 2% SBC reduced decay incidence after storage and shelf life simulation by four to seven-fold, to a commercially acceptable level of 6–7%, compared to untreated or waxed-treated controls. This treatment also maintained the fresh and blemish-free appearance of the fruit at harvest. Higher concentrations of SBC (3%) were phytotoxic and significantly reduced general fruit appearance. A trial shipment by sea transport to Europe demonstrated that 2% SBC incorporated into a wax coating maintained the marketability of ‘Galia’ melon fruits compared to that of untreated fruit. SBC can be an alternative biocide to the fungicide imazalil, thus eliminating unwanted residues on melon fruits.

Golden Delicious apples (Malus domestica Borkh) were heated for 4 days at 38 °C and then dipped in 2% CaCl2, or dipped in the solution without prior heating. Scanning electron micrographs of the fruit wax layer after three days of 0 °C storage showed that the heated apples had areas of amorphous wax and fewer surface cracks than unheated apples. There was less wax on the surface of heated than on unheated apples. Electron density scan of apple wax showed more calcium in outer than inner wax area of undipped but heated apples, while the opposite obtained in unheated apples. Dips in calcium raised the wax calcium level of the unheated apples more than the heated ones. Plasma emission spectrometry of calcium in apple peel and flesh after 5 months storage at 0 °C showed greater penetration of calcium from the dips into unheated apples, compared to heated apples. It is suggested that during the heat treatment the wax softens and fills in cracks while water loss pulls calcium towards the fruit surface. This continuous wax layer on heated fruit decreases the ability of external calcium to move into the apple.

Pectin methylesterase activity and the degree of methyl esterification of cell wall pectins were measured in Golden Delicious apples after a 4 day heat treatment at 38° and after subsequent storage at 0° of heated and unheated apples. Enzyme activity increased similarly during storage in both heated and unheated apples, although heated fruit softened much less than unheated. During storage, the degree of esterification decreased in both heated and unheated apples in water- and CDTA-soluble pectin, but not in insoluble pectin. In a comparison of three methods of determining methyl groups, similar values were obtained for degree of bulk esterification of apple cell walls, regardless of treatment. Results presented do not confirm a role for pectin methylesterase or for de-esterification in apple fruit softening.

Sanosil-25 is a universally applicable disinfectant compound that is highly effective against pathogenic bacteria, fungi, algae, viruses and amoebae. The compound contains 48% hydrogen peroxide (H 2 O 2 ) and 0.05% silver ion (Ag + ) as a stabilizing agent. The ED 50 for spore inhibition in vitro was 0.09% and 0.18% for Botrytis cinerea and Alternaria alternata , respectively. Germination was completely inhibited at concentrations of 0.5% and 0.7% for B. cinerea and A. alternata , respectively. The ED 50 values for mycelial growth inhibition were 0.6% and 0.7% for B. cinerea and A. alternata , respectively, but for complete inhibition the effective concentrations were 1.5% and 2.0%. The effective exposure time of fungal spores was inversely related to the concentration used. Dipping commercially harvested eggplants and sweet red peppers in 0.5% Sanosil-25 reduced decay development after storage and shelf-life to a commercially acceptable level compared with an untreated control.

Prestorage heating (38° for four days) of apples (Malus domestica, cv Golden Delicious) leads to enhanced retention of fruit firmness during stor

Mature green tomatoes (Lycopersicon esculentum) were held at 38°C for 3 days and then placed at 12°C for 2 weeks or 2°C for 3 weeks, before being removed to 20°C for 5 days. During the heat treatment, ethylene production, lycopene synthesis, chlorophyll and cell wall degradation were all inhibited, while respiration was enhanced. The tomatoes held at 12°C ripened during storage and the heat-treated tomatoes ripened faster. At the end of storage and shelf-life the heated tomatoes were redder and had higher soluble solids content than control tomatoes. The tomatoes held at 2°C did not ripen during storage. After removal to 20°C, control tomatoes developed chilling injury, while heated tomatoes ripened normally. Prestorage heat treatment of mature green tomatoes permits storage for longer periods of time and at lower temperatures than currently recommended with no loss of their ability to ripen normally.

The maximum storage life ‘Triumph’ persimmons in modified atmosphere (MA) packs of 0.08 mm low-density polyethylene was 8 weeks when packed under vacuum and 20 weeks when packed under nitrogen. The storage life could be extended to 7 months by storing ggibberellin-treated fruit in air at −1C°C prior to MA packaging. The factor which limited further extension of the storage life of the fruit under these conditions was the accumulation of ethanol and acetaldehyde, which caused development of off-flavors and tissue browning, respectively.

Summary In a climacteric fruit such as apple, ethylene synthesis increases during ripening and cyanide is stoichiometrically produced with ethylene. β-cyanoalanine synthase (CAS) activity was found to increase in ripening apple from the preclimacteric to climacteric and to decrease in the post-climacteric stage. In the non-climacteric fruit pepper, ethylene production and CAS activity was 250 fold and 30 fold lower, respectively, than in preclimacteric apples. Treating peppers with ethylene induced a transient increase in ethylene production and a longer lasting rise in CAS activity. Both fruits evidenced cyanide insensitive respiration, apple at all stages of ripeness and pepper from the turning stage onward. The results are discussed with regard to mechanisms in fruit that protect tissue function against increasing amounts of cyanide.